Multicell battery comprising duplex electrode utilizing conductive plastic carrier strip

ABSTRACT

Duplex electrodes are constructed by placing intermittent deposits of positive and negative electrodes on opposite sides of a continuous, electrically conductive plastic carrier strip. The duplex electrodes are then assembled into multicell batteries. The assembly preferably occurs while the duplex electrodes are structurally and electrically connected by the continuous plastic carrier strip after which the carrier strip is subsequently cut between duplex electrodes to obtain structurally and electrically unconnected batteries. Alternatively, the carrier strip may be cut between duplex electrodes before those electrodes are assembled into multicell batteries.

United States Patent Bergum et a1.

[11] 3,770,505 7 Nov. 6, 1973 1 MULTICELL BATTERY COMPRISING DUPLEXELECTRODE UTILIZING CONDUCTIVE PLASTIC CARRIER STRIP [75] Inventors:Bernard C. Bergum, Monona; John M. Bilhorn, Edgerton; Kenneth H. Kenyon,Madison; William R. Macaulay, Madison; John A.

v Youngquist, Madison, all of Wis.

[73] Assigriee: ESB Incorporated, Philadelphia, Pa.

[22] Filed: Feb. 25, 1972 [21] Appl. No.: 229,597

Related [1.8. .Application Data [62] Division of Ser. No, 100,257, Dec.21, 1970, Pat. No.

[52] US. Cl...... 136/10, 136/1 11 [51] Int. Cl. I-I01m 39/06 [58] Fieldof Search 136/10, 111, 108,

[56] References Cited UNITED STATES PATENTS 2,519,054 8/1950' Woodring136/111 2,684,989 7/1954 Wilburn.... 136/112 2/1955 Reiner 136/111 I I IPrimary ExaminerAnthony Skapars Att0rney-Robert H. Robinson et a1.

ABSTRACT Duplex electrodes are constructed by placing intermittentdeposits of pos itive and negative electrodes on op- I posite sides of acontinuous, electrically conductive plastic carrier strip.

The duplex electrodes are then assembled into multicell batteries, Theassembly preferably occurs while the duplex electrodes are structurallyand electrically connected by the continuous plastic carrier strip afterwhich the carrier strip is subsequently cut between duple andelectrically un x electrodes to obtain structurally connected batteries.Alternatively,

the-carrier strip may be cut between duplex electrodes before thoseelectrodes are assembled into multicell batteries.

2 Claims, 4 Drawing Figures DUPLEX 50 ELECTRODE PATENTEDImv 6 I975 73770.505

SHEET 1 OF 2 250,NE6ATWE ELECTRODE APPI. I QATOIZ BQNEGATIVE. ELECTRODEDEPOSITS I I I I 1 2.0, POSITIVE ELECTRODE DEPOSITS 50, ELECTRICALLYCONDUCTIVE PLASTIC CARRIER STRIP Z20, POSITIVE ELECTRODE Z50 APPLICATORMULTICELL BATTERY COMPRISING DUPLEX ELECTRODE UTILIZING CONDUCTIVEPLASTIC CARRIER STRIP This is a division of application Ser. No.100,257, filed Dec. 21, I970, now US. Pat. No. 3,694,266.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionconcerns duplex electrode: (also known as bipolar electrodes) in whichdeposits of positive and negative electrodes are intermittently placedon opposite sides of a continuous, electrically conductive plasticcarrier strip. The methods of constructing duplex electrodes and ofassembling those electrodes into multicell batteries are claimed, as arethe batteries.

2. Description of the Prior Art In the construction of a multicellbattery three essential requirements must be met: a member which isimpervious to the electrolyte of the battery must be used betweenadjacent cells to seal one cell from the next; some means must beprovided by which electrical current may be conducted between thepositive electrode in one cell and the negative electrode in an adjacentcell; and the electrolyte impervious member and the electrical conductormeans must not create any undesired reactions in the battery. Otherdesirable attributes are that there be low electrical resistancesbetweenthe positive electrode of one cell and the negative electrode of anadjacent cell and that the battery be constructed using inexpensivematerials and methods.

One technique for constructing multicell batteries is with the use ofduplex electrodes, also known as bipolar electrodes. A duplex electrodeis a separately constructed assembly in which an electrolyte impervious,electrochemically nonreactive member which eventually divides one cellfrom an adjacent cell has a positive electrode on one side and anegative electrode on the other side.- After being so constructed, theduplex electrode is subsequently assembled into a multicell battery. Theelectrolyte impervious, electrochemically nonreactive member will alsomeet the third essential requirement if it is made from an electricallyconductive material.

SUMMARY OF THE INVENTION With this invention duplex electrodes areconstructed by placing positive and negative electrodes in contact withopposite sides of a continuous, electrically conductive plastic carrierstrip. Use of the carrier strip as a substrate permits the positive andnegative electrodes to be made from compositions which, during theconstruction of the duplex electrode, are unable or poorly suited tofunction as a substrate. Use of an electrically conductive carrier strippermits electrical current to be conducted between the electrodeswithout additional components or assembly steps.

The positive and negative electrodes are applied in intermittentdeposits along the carrier strip with a deposit of positive electrodebeing centered opposite a deposit of negative electrode. During thisconstruction process the resulting duplex electrodes are structurallyand electrically connected together. The structural connection isdesirable because high speed production machinery is better able toprocess flexible continuous strips than individual pieces. The duplexelectrodes are thenv assembled into multicell batteries. The assemblypreferably occurs while the duplex electrodes are structurally andelectrically connected by the continuous plastic carrier strip afterwhich the carrier strip is subsequently cut between duplex electrodes toobtain structurally and electrically unconnected batteries.Alternatively, the carrier strip may be cut between duplex electrodesbefore those electrodes are assembled into multicell batteries.

. BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic diagramshowing a continuous, electrically conductive plastic carrier stripbeing passed to the applicators which place intermittent deposits ofpositive and negative electrodes in contact with the carrier strip.

FIG. 2 is an oblique view of a multicell battery containing duplexelectrodes made according to this invention.

FIG. 3 illustrates a typical cross-section of the battery shown in FIG.2 taken along the line A--A of FIG. 2. The thickness of the battery isshown greatly magnified for purposes of illustration.

FIG. 4 illustrates a portion of the electrically conduc tive carrierstrip with patches of positive and negative electrodes placed on theopposite sides thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagramshowing a continuous, electrically conductive plastic carrier strip 50from a roll or some other source of supply 250 being passed to thepositive and negative electrode applicators 220 and 230, respectively,where the applicators place intermittent patch deposits of positive andnegative electrodes 20 and 30, respectively, on opposite sides of thecarrier strip from each other. Each patch deposit of negative electrodeis substantially opposite a patch deposit of positive electrode. Theapplicators 220 and 230 may be spaced opposite one another so that theymake their opposing patch deposits simultaneously, or they may be spacedapart so that one applicator first makes its patch deposit and later theother applicator makes the opposing patch deposit. FIG. 4 illustrates aportion of the electrically conductive carrier strip with patches ofpositive and negative electrodes placed on the opposite sides thereof.It will be understood by those skilled in the art that a segment of thecarrier strip having a positive and negative electrode on its oppositesides defines a duplex electrode, also known as a bipolar electrode Ascan be seen from FIGS. 1 and 4, the duplex electrodes are structurallyand electrically connected together immediately after the carrier strippasses by the second of the two applicators; these physical andelectrical connections between duplex electrodes subsequently must bebroken, but this can be done either before or after the duplexelectrodes are assembled into multicell batteries.

The eventual multicell battery product is the same whether the duplexelectrodes constructed as shown in FIG. 1 are assembled into multicellbatteries before or after being structurally and electricallyunconnected from each other. FIG. 2 shows such a multicell battery 5 inan oblique view. FIG. 3 shows a portion of the multicell battery 5 in amagnified cross-section and illustrates members of the battery, each ofwhich will be deelectrode 30-A, and at least one duplex electrodebetween electrodes 20-A and 30-A, each duplex electrode being of thetype constructed by the method shown in FIG. 1. As shown in FIG. 3, aduplex electrode comprises the combination of a segment of electricallyconductive plastic carrier strip which functions as the intercellconnector of the duplex electrode, together with deposits of positiveand negative electrodes 20 and 30 respectively on the opposite sides ofthe segment. The multicell battery 5 also includes an electrolyteimpregnated separator 40 between each positive electrode 20 or 20-A andeach negative electrode 30 or 30-A. The multicell battery thus includesat least two cells, each cell comprising the combination of a positiveelectrode 20 or 20-A, a negative electrode 30 or 30-A and an electrolyteimpregnated separator 40 between the electrodes. Liquid imperviouslayers 80 and 90 which also function as current conducting means are incontact with the outer electrodes 20-A and 30 A respectively. Metalcurrent collectors 60 and 70 which also function as vapor barriers areon the outside of layers 80 and 90. Electrolyte impervious sealing meansand electrical insulating means around the electrolyte impregnatedseparators 40 are designated by the numeral 100.

Numerous advantages result from the construction illustratedschematically in FIGS. 1 and 4 and described above. Use of the carrierstrip as a substrate permits the electrodes to be made from compositionswhich, during the construction of the duplex electrodes, are unable orpoorly suited to be produced as continuous strips. Examples ofelectrodes which are unable or poorly suited to be produced ascontinuous strips include electrodes comprising particles of activematerial contained in and dispersed throughout a porous matrix; flamespray deposits; and vapor deposits.

The conductive carrier strip also permits current to be conductedbetween the positive and negative electrodes in a duplex electrodewithout the use of any other electrically conductive members.

The electrically conductive plastic also has the advantage of beingelectrochemically inert in the battery. While continuous carrier stripsmade from metals such as zinc, aluminum, or steel could be used toachieve some of the advantages attained with this invention, thesemetals tend to produce unwanted electrochemical reactions with theelectrodes on one or both sides of the carrier strip unless the stripsare coated on one or both sides with an electrolyte impervious,electrically conductive, electrochemically nonreactive material. Metalcarrier strips which by themselves are electrochemically nonreactive,such as titanium, tantalum or gold are excessively expensive.

The use of the continuous carrier strip as a substrate along whichintermittent deposits of electrodes are applied is also advantageousfrom the viewpoint of manufacturing techniques. Modern high speedproduction machinery is better able to handle flexible, continuousstrips with deposits than a succession of flexible, individual pieces.Maximum advantage of this principle may be attained in conjunction withthis invention by using the continuous strip as a processing implementthroughout the construction of duplex electrodes and the subsequentassembly of those electrodes into multicell batteries, leaving the stepof cutting the carrier strip into segments until all other assemblysteps required to assemble the multicell batteries have been taken. Inthis regard, it is preferred to assemble a plurality of structurally andelectrically unconnected multicell batteries by beginning with theconstruction of duplex electrodes which are structurally andelectrically connected together by the continuous electricallyconductive plastic carrier strip. This consists of placing intermittentdeposits of positive and negative electrodes on the carrier strip asshown in FIG. 1 so that each patch deposit of negative electrode is onthe other side of the strip from and substantially centered opposite apatch deposit of positive electrode. The next step in the preferredprocess consists of assembling multicell batteries which arestructurally and electrically connected together by at least one of thecarrier strips having positive and negative electrodes depositedthereon, a step which comprises the acts of: placing in alignment atleast one such carrier strip between outer positive and outer negativeelectrodes so that a duplex electrode is between an outer positiveelectrode and an outer negative electrode; placing an electrolyteimpregnated separator between each positive and negative electrode;sealing around the perimeter of each electrolyte impregnated separatorto produce a liquid impervious seal; sealing a liquid impervious layeraround the electrodes and electrolyte impregnated separators; and,connecting to each outer positive electrode electrically conductivemeans which extend to the exterior of the liquid impervious layer andconnecting to each outer negative electrode additional electricallyconductive means which extend to the exterior of the liquid imperviouslayer. After the multicell batteries have been so assembled, eachcarrier strip is then cut between duplex electrodes to obtainstructurally and electrically unconnected multicell batteries; thecarrier strip may be cut between each successive pair of duplexelectrodes, or it may be cut into increments each of which contains twoor more duplex electrodes so that the resultant batteries structurallyconnected by the increment are electrically connected in parallel.During the assembly of the multicell batteries additional components maybe processed in the form of continuous strips; alternatively, each ofthese additional components may also comprise a succession ofstructurally unconnected components placed along the continuousconductive plastic carrier strip.

FIG. 3 is helpful in illustrating these concepts. The multicell battery5 shown in FIG. 3 may be made by using three of the electricallyconductive plastic carrier strips 50 with positive and negativeelectrodes 20 and 30 applied intermittently on the opposite sides ofeach as shown in FIGS. 1 and 4. The electrolyte impregnated separators40 shown in FIG. 3 were assembled into the battery as structurallyunconnected components. The components 60, 70, and were assembled intothe multicell battery 5 as continuous strips, although they also couldhave been components whichhave no structural connection with each otherwhen assembled into successive multicell batteries. The cutting of thethree electrically conductive plastic carrier strips plus the cutting ofany other continuous strips used in constructing the multicell battery 5may be the last step in the construction of a plurality of multicellbatteries, thereby retaining the advantages of processing continuousstrips rather than individual unconnected pieces for as much of theassembly process as possible.

It is not essential that the cutting of the continuous, electricallyconductive plastic carrier strip into structurally and electricallyunconnected duplex electrodes be postponed until all other steps in theassembly of multicell batteries are complete. The cutting of the stripsmay, for instance, be done immediately after the positive and negativeelectrodes are applied intermittently on opposite sides of the carrierstrips and the unconnected duplex electrodes may then be assembled intomulticell batteries. If this sequence of steps is taken, then theassembly of a multicell battery after the cutting of the carrierstrip'comprises: placing at least one of the structurally andelectrically unconnected duplex electrodes between an outer positiveelectrode and an outer negative electrode; placing an electrolyteimpregnated separator between each positive and negative electrode;sealing around the perimeter of each electrolyte impregnated separatorto produce a liquid impervious seal; sealing a liquid impervious layeraround the electrodes and electrolyte impregnated separators; and,connecting to the outer positive electrode electrically conductive meanswhich extend to the exterior of the liquid impervious layer andconnecting to the outer negative electrode additional electricallyconductive means which extend to the exterior of the liquid imperviouslayer. The unconnected duplex electrodes could be assembled intomulticell batteries as described above in a process in which some othercomponent of the finally constructed batteries was used in the form of acontinuous carrier strip during some or all of the-assembly steps; forinstance, the outside layers could be continuous carrier strips and theduplex electrodes, electrolyte impregnated separators, and outerelectrodes could then be placed along those continuous strips, with thecutting of those strips to produce structurally unconnected multicellbatteries being postponed until after all other assembly steps have beenconcluded.

The composition of each of several of the members in the battery maytake alternative forms, and the compositions of those members will nowbe discussed.

The positive electrodes and 20-A may each comprise particles ofelectrochemically positive active material contained in and dispersedthroughout a binder matrix. The positive active material conventionallyis divided into tiny particles so as to increase the rate at which theelectrochemical reactions can occur by increasing the surface area wherethey occur. The binder increases the electronic conductivity of theduplex electrode, increases the structural integrity within the positiveelectrode, and adheres the positive electrode to the carrier strip.Since electrolyte must have access to the surface of the active materialparticles, the electrode must be made sufficiently porous so that theelectrolyte may difi'use throughoutthe electrode rapidly and thoroughly.Preferably the pores in the electrode are produced by the evaporation ofliquid during the construction of the electrode; the evaporating liquidmay be part'of a dispersion binder system in which the solid bindercontained in the finally constructed electrode comprises tiny particlesof binder material dispersed throughout and not dissolved in the liquidwhile the electrode is being constructed, or the evaporating liquid maybe part of a solution binder system in which the solid binder containedin the finally constructed electrode is dissolved in the liquid which islater evaporated. The porosity of the positive electrodes may beincreased as the discharge rate desired in the battery is increased.Electrodes may also be constructed using combinations of the dispersionand solution systems. Alternatively, the pores might be produced by thedissolving of a solid which was present during construction of theelectrode or by passing gases through or generating gases within theelectrodes at controlled rates during electrode construction. Thepositive electrodes 20 and 20-A may, and preferably will also containamounts of a good electrical conductor such as carbon or graphite toimprove the electrical conductivity between the active materialparticles, the positive active material particles themselves generallybeing relatively poor conductors of electricity. The conductivity of theactive material particles together with the conductivity of the binderitself will influence the amounts of conductors added to the electrode.The electrodes 20 and 2(l-A may also contain if desired small amounts ofadditional ingredients used for such purposes as maintaining uniformdispersion of active material particles during electrode construction,aiding the diffusion of electrolyte through the pores of the finallyconstructed electrodes, controlling viscosity during processing,controlling surface tension, controlling pot life, or for other reasons.

The negative electrodes 30 and 30A may comprise spray or vapor depositsof metals or may comprise tiny particles of metals contained in anddispersed throughout a binder matrix. If the negative electrodes utilizea binder matrix, in general the same considerations regarding thatmatrix apply to the negative electrodes as do for the positiveelectrodes except that no electrical conductor may be needed to achievedesired electrical conductivity between the active material particlessince the negative active materials are generally better conductors thanare the positive materials. When the negative electrodes utilize abinder matrix, the binder system need not be the same as the one used inthe positive electrodes, and even if it is the proportions of binder,active material particles, and other ingredients in the negativeelectrodes may have a different optimum than the proportions ofanalogous ingredients in the positive electrode. The initial porosity ofthe negative electrodes may sometimes be less than that of the positiveelectrodes, since the negative electrode discharge reaction products aresometimes dissolved in the battery electrolyte. The porosity of thenegative electrodes may be increased as the discharge rate desired inthe battery is increased. The negative electrodes 30 and/or 30-A mayalso comprise thin sheets or foils of electrochemically negativematerial.

It is apparent that electrodes which comprise particles of activematerial would be unable or poorly suited to be produced as continuousstrips. They should therefore be deposited upon a substrate which, inthe case of this invention is the electrically conductive plasticcarrier strip.

Between each positive electrode 20 and 20-A and each negative electrode30 and 30-A is an electrolyte impregnated separator 40, the theoreticalrequirements of which are that it contain electrolyte as well asphysically separate and prevent contact between the electrodes. Adeposit of gelled electrolyte could by itself serve both functions if ofproper thickness and/or consistency. The alternative construction uses adeposit of gelled or fluid electrolyte with a separator which isdistinct from and in addition to the electrolyte, the separatorproviding added insurance against direct contact between the electrodesand acting as an absorbent material into which the electrolyte may beimpregnated. Both alternative constructions may, however, be viewed asbeing forms of electrolyte impregnated separators. Where the separatoris distinct from and in addition to the electrolyte, the separator maybe made from a wide variety of materials including the fibrous andcellulosic materials which are conventional in battery construction aswell as from woven or non-woven fibrous materials such as polyester,nylon, polyethylene and glass.

Another essential of the multicell battery is a liquid impervious layercomprising members 80 and 90 sealed around the electrodes andelectrolyte impregnated separators as shown in FIG. 3. When a battery isin storage waiting to be placed into service there is an opportunity forliquids from the electrolyte to escape from the battery, leaving thebattery incapable of performing as desired when later placed into use.Also during discharge the battery may produce liquid byproducts whichare corrosive, poisonous or otherwise harmful, and it is desirable toprevent these liquids from escaping from the battery. The liquidimpervious layer provides means for preventing or minimizing the loss ofthese liquids.

The multicell battery 5 must also be provided with means for conductingelectrical current between the outer positive electrode 20-A and theexterior of the liquid impervious layer and additional means forconducting electrical currrent between the outer negative electrode 30-Aand the exterior of the liquid impervious layer. This additionalrequirement of the battery may be met by the liquid impervious layermembers 80 and 90 themselves by constructing those members from aconductive material such as an electrochemically inert, electricallyconductive plastic, and such a construction is shown in FIG. 3. As analternative to the conductive plastic, metals which are eitherthemselves electrochemically nonreactive or are made so by appropriateconductive, nonreactive coatings may be used for the liquid imperviouslayer. Another alternative construction not illustrated in the drawingsis to use a liquid impervious layer which is made from an electricallynonconductive material and then extend separate conductive means fromthe end electrodes 20-A and 30-A through or around the edge of thenonconductive, liquid impervious layer so that current may be withdrawnfrom the battery. It is to be understood that all of these alternativeconstructions are encompassed by the general statement that a liquidimpervious layer is sealed around the electrodes and electrolyteimpregnated separators, that electrically conductive means are connectedto the outer positive electrode 20-A which extend to the exterior of theliquid impervious layer, and that additional electrically conductivemeans are connected to the outer negative electrode 30-A which extend tothe exterior of the liquid impervious layer.

Two additional components, members 60 and 70, are shown in FIG. 3 andare illustrated because they may be used in the construction of themulticell battery produced by this invention. It should be understood,however, that the present invention does not require the use of members60 and 70. Those members are metal foils or sheets, e.g., steel foil,which function both as vapor barriers to prevent evaporation ofelectrolyte from the battery and as current collecting means. Where anonmetallic, nonconductive vapor barrier is used instead of steel foil,additional means must be provided to conduct current from the exteriorof the liquid impervious layer (members 80 and 90) to the exterior ofthe vapor barrier. Where vapor barriers such as the members 60 and shownin FIG. 3 are used in the battery, they may be laminated to the liquidimpervious layers and if desired.

Liquid impervious sealing means must be provided around each electrolyteimpregnated separator 40 to prevent electrolyte loss from the batteryand to prevent the electrolyte of one cell from migrating to anothercell around the perimeter of an intercell connector. Adhesive membersshown in FIG. 3 may serve as the needed liquid impervious sealing means.

By being made from an electrically nonconductive adhesive, members 100also serve an additional purpose, that of preventing undesiredelectrical connections between the electrically conductive intercellconnector and other electrically conductive members of the battery.

The electrically conductive plastic used in the continuous carrier strip50 and also shown in items 80 and 90 in FIG. 3 may be produced bycasting, extrusion, calendaring, or other suitable techniques. Theconductive plastics may be made, for example, from materials such aspolymers loaded with electrically conductive particles and containingvarious stabilizers and/or plasticizers. The conductive particles may becarbonaceous materials such as graphite or acetylene black, or metallicparticles may also be used. Polymers which by themselves aresufficiently conductive may also be used. The conductive plastic,whether loaded or unloaded, must be made from a composition which iscompatible with other components of the battery. For batteries usingLeClanche and moderately concentrated alkaline electrolytes, theconductive plastic may be made for example, from materials such aspolyacrylates, polyvinyl halides, polyvinylidene halides,polyacrylonitriles, copolymers of vinyl chloride and vinylidenechloride, polychloroprene, and butadiene-styrene orbutadieneacrylonitrile resins. For batteries using strongly alkalineelectrolytes, polyvinylchloride and polyolefins such as polyethylene andpolyisobutylene may be used in the preparation of the conductiveplastic. For batteries using acid electrolytes such as sulfuric acid,polyvinyl halides, copolymers of vinyl chloride, and vinylidene chloridemay be used.

While it is preferred to employ the LeClanche electrochemical system(comprising manganese dioxide positive active material, zinc negativeactive material, and an electrolyte comprising ammonium chloride and-/or zinc chloride), the multicell battery 5 of this invention may employa wide variety of positive and negative electrode materials and a widevariety of electrochemical systems including both primary and secondarysystems. Among the positive electrode materials are such commonly usedinorganic metal oxides as manganese dioxide, lead dioxide, nickeloxyhydroxide, mercuric oxide and silver oxide, inorganic metal halidessuch as silver chloride and lead chloride and organic materials capableof being reduced such as dinitrobenzene and azodicarbonamide compounds.Among the negative electrode materials are such commonly used metals aszinc, aluminum, magnesium, lead, cadmium, and iron. This invention mayemploy the electrolytes commonly used in the LeClanche system (ammoniumchloride and/or zinc chloride), various alkaline electrolytes such asthe hydroxides of potassium, sodium and/or lithium,

acidic electrolytes such as sulfuric or phosphoric aicd, and nonaqueouselectrolytes, the electrolytes of course being chosen to be compatiblewith the positive and negative electrodes.

Among the wide variety of electrochemical systems which may be used inthe multicell battery are those in which the positive electrodescomprise manganese dioxide, the negative electrodes comprise metals suchas zinc, aluminum, or magnesium, and the electrolyte substantiallycomprises an acidic solution of inorganic salts. Another commonly knownsystem useful in the battery 5 is the alkaline manganese system in whichthe positive electrodes comprise manganese dioxide, the negativeelectrodes comprise zinc, and the electrolyte substantially comprises asolution of potassium hydroxide. Other aqueous electrolyte systemsincluding those of nickel-zinc, silver-zinc, mercury-zinc,mercurycadmium, and nickel-cadmium may also be used. Systems employingorganic positive electrodes and acidic electrolytes may also be used,including rechargeable systems using azodicarbonamide compoundelectrodes and LeClanche electrolyte.

We claim:

1. A multicell battery comprising the combination of:

a. an outer positive electrode;

b. an outer negative electrode;

0. at least one duplex electrode between the outer positive and negativeelectrodes, each duplex electrode comprising the combination of i. asegment of an electrically conductive plastic, ii. a deposit of positiveelectrode on one side of the segment, and iii. a deposit of negativeelectrode on the other side of the segment;

(1. a liquid electrolyte impregnated separator between each positive andnegative electrode;

e. a liquid impervious layer sealed around the electrodes andelectrolyte impregnated separators;

f. means for conducting electrical current between the outer positiveelectrode and the exterior of the liquid impervious layer and additionalmeans for conducting electrical current between the outer negativeelectrode and the exterior of the liquid impervious layer; and

g. means around the perimeter of each electrolyte impregnated separatorfor producing a liquid impervious seal, the deposits of positive andnegative electrodes on the sides of the conductive plastic segment beingfurther characterized as comprising mixtures of electrochemically activematerial particles and a nonmetallic binder material uniformly dispersedthroughout the thickness of the electrodes, the nonmetallic bindermaterials in each of the positive and negative electrodes being furthercharacterized as i. adhering the active material particles in theelectrode together,

ii. being substantially insoluble in the liquid electrolyte andpermanently bonding the electrode to the conductive plastic intercellconnector segment so that there can be electronic conductivity betweenthe electrode and the intercell connector and so that the electrode andintercell connector are united into a unitary structure without anyadditional conductive adhesive between the electrode and the intercellconnector, and

iii. providing a matrix which is sufficiently porous so that theelectrolyte may diffuse throughout the electrode.

2. The multicell battery of claim 1 in which the positive electrodescomprise manganese dioxide active material, the negative electrodescomprise zinc active material, and the electrolyte comprises a solutionof ammonium chloride and/or zinc chloride.

2. The multicell battery of claim 1 in which the positive electrodescomprise manganese dioxide active material, the negative electrodescomprise zinc active material, and the electrolyte comprises a solutionof ammonium chloride and/or zinc chloride.